668 research outputs found

    Neural Audio: Music Information Retrieval Using Deep Neural Networks

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    The use of deep neural networks has exploded in popularity recently. Thinking that music information retrieval should not be left out of this trend in machine learning, we explore two different applications of this technology in the field. The first we looked at was genre identificaton, using the initial categories of \u27popular music,\u27 \u27art music,\u27 and \u27traditional music.\u27 This was found to be a difficult problem - classifying music into these categories can be challenging even for experts, and assembling a large dataset for use in training represents a significant problem. The second approach we took to using these techniques was looking at instrument identification, specifically for the purpose of identifying the time and category (from guitar, vocal, or drum ) of solos in popular music

    Thermodynamically stable lithium silicides and germanides from density-functional theory calculations

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    Density-functional-theory (DFT) calculations have been performed on the Li-Si and Li-Ge systems. Lithiated Si and Ge, including their metastable phases, play an important technological r\^ole as Li-ion battery (LIB) anodes. The calculations comprise structural optimisations on crystal structures obtained by swapping atomic species to Li-Si and Li-Ge from the X-Y structures in the International Crystal Structure Database, where X={Li,Na,K,Rb,Cs} and Y={Si,Ge,Sn,Pb}. To complement this at various Li-Si and Li-Ge stoichiometries, ab initio random structure searching (AIRSS) was also performed. Between the ground-state stoichiometries, including the recently found Li17_{17}Si4_{4} phase, the average voltages were calculated, indicating that germanium may be a safer alternative to silicon anodes in LIB, due to its higher lithium insertion voltage. Calculations predict high-density Li1_1Si1_1 and Li1_1Ge1_1 P4/mmmP4/mmm layered phases which become the ground state above 2.5 and 5 GPa respectively and reveal silicon and germanium's propensity to form dumbbells in the Lix_xSi, x=2.33βˆ’3.25x=2.33-3.25 stoichiometry range. DFT predicts the stability of the Li11_{11}Ge6_6 CmmmCmmm, Li12_{12}Ge7_7 PnmaPnma and Li7_7Ge3_3 P3212P32_12 phases and several new Li-Ge compounds, with stoichiometries Li5_5Ge2_2, Li13_{13}Ge5_5, Li8_8Ge3_3 and Li13_{13}Ge4_4.Comment: 10 pages, 5 figure

    Time Evolution and Deterministic Optimisation of Correlator Product States

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    We study a restricted class of correlator product states (CPS) for a spin-half chain in which each spin is contained in just two overlapping plaquettes. This class is also a restriction upon matrix product states (MPS) with local dimension 2n2^n (nn being the size of the overlapping regions of plaquettes) equal to the bond dimension. We investigate the trade-off between gains in efficiency due to this restriction against losses in fidelity. The time-dependent variational principle formulated for these states is numerically very stable. Moreover, it shows significant gains in efficiency compared to the naively related matrix product states - the evolution or optimisation scales as 23n2^{3n} for the correlator product states versus 24n2^{4n} for the unrestricted matrix product state. However, much of this advantage is offset by a significant reduction in fidelity. Correlator product states break the local Hilbert space symmetry by the explicit selection of a local basis. We investigate this dependence in detail and formulate the broad principles under which correlator product states may be a useful tool. In particular, we find that scaling with overlap/bond order may be more stable with correlator product states allowing a more efficient extraction of critical exponents - we present an example in which the use of correlator product states is several orders of magnitude quicker than matrix product states.Comment: 19 pages, 14 figure

    F17RS SGR No. 17 (Coaxial Cables)

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    A RESOLUTION To urge and request the Residence Hall Association (RHA) to provide coaxial cables for residents living in the Residence Hall

    Reporting of conflicts of interest in oral presentations at medical conferences : a delegate-based prospective observational study

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    Β© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.Peer reviewedPublisher PD

    Energetics of hydrogen/lithium complexes in silicon analyzed using the Maxwell construction

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    We have studied hydrogen/lithium complexes in crystalline silicon using density-functional-theory methods and the ab initio random structure searching (AIRSS) method for predicting structures. A method based on the Maxwell construction and convex hull diagrams is introduced which gives a graphical representation of the relative stabilities of point defects in a crystal and enables visualization of the changes in stability when the chemical potentials are altered. We have used this approach to study lithium and hydrogen impurities in silicon, which models aspects of the anode material in the recently-suggested lithium-ion batteries. We show that hydrogen may play a role in these anodes, finding that hydrogen atoms bind to three-atom lithium clusters in silicon, forming stable {H,3Li} and {2H,3Li} complexes, while the {H,2Li} complex is almost stable.Comment: (5 pages, 4 figures

    Approaches to Measuring Attendance and Engagement

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    In this paper, we argue that, where we measure student attendance, this creates an extrinsic motivator in the form of a reward for (apparent) engagement and can thus lead to undesirable behaviour and outcomes. We go on to consider a number of other mechanisms to assess or encourage student engagement – such as interactions with a learning environment – and whether these are more benign in their impact on student behaviour i.e. they encourage the desired impact as they are not considered threatening, unlike the penalties associated with non-attendance. We consider a case study in Computer Science to investigate student behaviour, assessing different metrics for student engagement, such as the use of source control commits and how this measure of engagement differs from attendance

    Timeliness and content of retraction notices for publications by a single research group

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    Funding The study received no specific funding. MB is the recipient of an HRC Clinical Practitioner Fellowship. The Health Services Research Unit is funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. The authors are independent of the HRC. The HRC had no role in study design, the collection, analysis, and interpretation of data, the writing of the article, or the decision to submit it for publication.Peer reviewedPostprin
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